well, it decreases estrogen and increases testosterone, what did you expect?
there are studies on letro and adex in (natty) men that also show more lean mass and less bodyfat over time
this obviously doesnt work for AAS users (well, maybe indirectly but probably less dramatic and you cant account any gains/losses to the aromasin use)
aromasin is the only of the AIs that has a steroidal structure, so it may have some direct activity too (or its metabolites, as its mentioned in the article)
it still wont do a thing for anyone whos enhanced imo.